Bob tipped us with his latest project, it’s a 9V to 1kV DC-DC converter using CD4011 IC to produce a square wave and a IRF530 transistor to drive the transformer.
Finally, I have made a new high voltage supply based on an inverter transformer and voltage doubler. It seems to be ok for this job, but it can be used in various other applications so I’m presenting it in a separate entry.
Warning! the device produces high voltage that can be lethal, if you want to build it, please take cautions.
In this episode Shahriar repairs a Stanford Research Systems Model PS350 5000V-25W High Voltage Power Supply. The unit continuously displays 2.5kV without the output being enabled and produces no output voltage. Verification of power supply voltages reveals the issue is linked to a disconnected 15V voltage regulator IC. After the repair, the output voltage is verified with both positive and negative outputs. The principle operation of the instrument as well as the Cockroft-Walton high voltage generator is reviewed.
Teardown & Repair of a Stanford Research PS350 5000V, 25W High Voltage Power Supply – [Link]
Kirlian photography is an interesting photographic technique of capturing corona discharge of objects. The images basically contain only edges in a form of blue glow. Note: one of those photos is visible in “The X files” intro – read the whole article to know why!
In this post I will present my minimalist approach with common materials and without complicated construction. The results aren’t that good as with more complex setups, but I think that they are still really interesting.
Kirlian photography – a simple way of taking it – [Link]
Old CRT monitor or TV is a great source of electronic components that can be used in DYI constructions. One of them is a flyback transformer that can provide 10-30kV output. The input voltage can be in a range from a couple of volts to over a dozen of volts, power consumption is a couple of watts. In my construction input voltage is 9V, power consumption is 5W.
A flyback transformer is driven by one or two transistors that should be also extracted from the same TV or monitor, those are high voltage transistors, that are hard to substitute and if bought separably can be expensive.
High voltage supply (10-30kV) made from CRT television flyback transformer – [Link]
WARNING: Before you start making anything please take a moment and read this:
This circuit is intended to be used for educational and experimental purposes (electrostatic experiences, franklin bell experiment, plasma generation, gas ionization, electronic igniter, testing of insulating materials…) this circuit should not leave the lab or your house, and it shouldn’t be used to harm to anybody, human or animal.
Do not attempt to replicate this circuit if you aren’t familiar with high voltages or intermediate electronics, high voltages are very dangerous.
High voltages can disrupt electronic equipment, so don’t keep phones, pacemakers or other sensible electronic devices near the supply.
I’m not responsible for the use given to this device and I’ve made all what it’s on my hands to include safety related information, and safety implementations to the circuit.
Follow the general security measures when dealing with high voltages, here you have a nice safety guide, please read it carefully before you continue.
A boost converter works in two stages, ON and OFF. In the ON stage the Semi-conductive Switch is conducting and current builds up in the inductor producing an electromagnetic field, this field stores energy. In the OFF stage the Semi-conductive Switch does not conduct and the electromagnetic field collapses. When the field collapses the energy stored in it can not escape through the Semi-conductive Switch so it goes through the diode and into the load/Capacitor at a much higher voltage. This happens several thousand times a second via the pulses from the NE555 Timer Chip and the result is being able to charge a high voltage capacitor from a low voltage source. Below is some aid for those of you who do not know electronics well.
Sure making a cap out of paper is fun and all, but making a high voltage one is even more fun!
You don’t need lots of money to make high voltage capacitors, in fact some pretty decent ones can be made with some cheap and readily available materials. This is because capacitors are very simple devices; consisting only of a dielectric and two plates. Most often a capacitor’s plates are just aluminum foil, and reynold’s wrap is easy enough to obtain, but what about the dielectric?
Enter the overhead projector sheet. Transparencies as they are commonly known as are nothing but acetate film, and while this is not the ideal dielectric for a capacitor it still does quite a good job. Typically a four mil OHP sheet can withstand 14kV before breaking down. As for obtaining them, the cheapest I have found these sheets is $10 for a box of 100, enough for about 16 capacitors.
How you make the capacitors is a rather trivial task, all that needs to be done is some cutting, flattening and rolling. Below I have an image that explains the process. Multiple sheets of OHP sheet are used to increase the capacitor’s voltage rating, and two sets of sheets are used so the capacitor can be rolled up.
rsdio writes: Although this circuit does not directly show how, you can use the same idea to make a 3.3 V tolerant I/O pin control an LED with a much higher voltage. The caveat is that all of the current still passes through the I/O pin, but at least you can control several LEDs in series to get more brightness without the necessary higher voltage posing a problem.
A Darlington transistor pair should allow the current to be increased beyond the I/O pin limits, thus breaking free from both voltage and current limits. The latter is left as an exercise well beyond the app note’s content. [via]
Although many LED-driver ICs operate at relatively low voltage, this application note shows how to operate the MAX6974 at higher voltage by adding a common-base-transistor level shifter, allowing it to drive multiple LEDs in series.
Control high-voltage LEDs with low-voltage pins – [Link]
Mark Rehorst build his own Van de Graaff generator and documented the procedure on the article below. Van de Graaff generator is a device capable of producing high voltages by collecting electrostatic charges on a large metal sphere. The high voltage generated is able to make peoples hair stand up! Check the article below for construction details. [via]